A cylinder block of a reciprocating engine is configured to provide motive force to a vehicle (car, truck). The cylinder block is an integrated structure including various machined components such as cylinders along with some or all of the associated surrounding structures (such as, coolant passages, intake and exhaust passages and ports, crankcase, etc.). The term engine block is often used synonymously with “cylinder block” although technically distinctions can be made between the cylinder block as a discrete unit versus the engine block having integrated components.
Machining of the components used in the engine block includes various processes in which a piece of raw material is cut into a desired final shape and size by a controlled material-removal process. The many processes that have this common theme, controlled material removal, are today collectively known as subtractive manufacturing, in distinction from processes of controlled material addition, which are known as additive manufacturing. Traditional machining processes include: turning, boring, drilling, milling, broaching, sawing, shaping, reaming, tapping, etc. Machine tools, such as lathes, milling machines, drill presses, or others, are used with a sharp cutting tool to remove material to achieve a desired geometry. Newer machining technologies include: electrical discharge machining, electrochemical machining, electron beam machining, photochemical machining, and ultrasonic machining.
A gauge or gage is used widely in metalworking. The gauge is a device (tool) used to make measurements on a machined component, such as the engine block. A wide variety of gauges exist which serve such functions, ranging from simple pieces of material against which sizes can be measured to complex pieces of machinery. There are two types of gauges (measuring tools): direct and indirect. Due to the realities of machining metal pieces, most measurements are of the plus/minus type; for example, the plus/minus type measurement may be recorded as 2.125 inches+/−0.0005 inches (42.00 mm+/−0.005 mm). The first number is the preferred size (dimension). The +/− number is the amount of variation between the preferred size and an acceptable size (preferred or target size). During inspection of a part or machined component, the preferred dimension is given. After measuring the machined component, a comparison is made between the measured size and the acceptable size to determine whether the measured dimension of the machined component is acceptable or not acceptable (and if found not acceptable, the machined component is rejected).
Accurate measurement of engine components, such as the dimensional aspects of the machined components used in the engine block, is critical to properly manufacture an acceptable engine block, both in terms of longevity and performance as well as profitability. Unfortunately, a component that was improperly machined and then inaccurately gauged (measured) adds unwanted time and/or cost to the process of manufacturing the engine block (or other components used in the vehicle).